[jenrator]

hello all i want to add a 20a circuit to an existing sub panel that runs my ac and heat. the circuit is for a 1.5 hp pool pump set up for 115v continous load.(plug type dont know what it draws) the sub panel is fed by a 45a breaker,the a/c draws from a 30a and draws 9.5 amps each leg the heat is connected to its own 15a breaker(wouldnt be on when pool pump is on) do i need to upgrade the 45a in the main panel? would it cause nuisance tripping on the 45a? Thanks

 

[secutanudu]

I don't think you'll have a problem. The only thing the pump would be competing with is the a/c. Even if the a/c used all 30A (it obviously doesn't), you still have a full 15A left....looks like (from google searches) 1.5 hp pool pumps use from 8-12 amps. I don't think you'll have a problem.

 

[jenrator]

tthat helpshanks Andrew

 

[kbsparky]

....looks like (from google searches) 1.5 hp pool pumps use from 8-12 amps. I don't think you'll have a problem.

That would be operating at 240 Volts. Double that number for 120 Volt operation.

 

[Missouri Bound]

A 120V 1.5HP motor should draw about 1100 watts.....that's just around 9 amps. You should be good to go.

 

[kbsparky]

A 120V 1.5HP motor should draw about 1100 watts.....that's just around 9 amps. You should be good to go.

Have you checked table 430.248 in the Code? It shows a 1½ HP motor requiring 20 Amps at 115 Volts.

Your calculations of using 746 watts per hp does not take power factor nor efficiency into consideration ....